We use grateful and thankful to express our thanks for something. Even if the two words are often used interchangeably, there is a difference between them. So, what is the difference between grateful and thankful?

GRATEFUL

Grateful is used to express our gratitude when somebody is kind to us or helps us in a way that will have a long-time effect.

Many thanks for helping us move into our new flat. We are so grateful.
I am particularly grateful to my supervisor for her support and encouragement.

You can feel grateful when you are in a third-world country and realise that at home you have access to fresh air and clean water.

You can use grateful when you make a request in a formal letter:

I would be grateful if you would send me your latest brochure.

THANKFUL

Thankful is used when you feel relieved that something dangerous or unpleasant did not happen.

We had a burglary last week. I’m so thankful that my computer was not stolen.
My brother had a nasty car accident. We are all thankful that he was not seriously injured.

A damaged car is being lifted on to a lorry. The image illustrates the difference between grateful and thankful.
A nasty car accident

You are also thankful when somebody has done something and the situation would have been much worse if they had not done anything.

To sum up, if you are grateful, you express gratitude to somebody for something they have done or given and if you are thankful, you feel relief or happiness over something.

The corresponding nouns are gratitude and thankfulness.